Target size analysis of estrogen receptor in cultured intact cells: change in receptor structure between subconfluency and superconfluency in culture.
MCF-7 human breast cancer cells were submitted to the tritiated antiestrogen tamoxifen aziridine, frozen at -170 degrees C, stored and irradiated at -78 degrees C in a calibrated Gammacell 60Co irradiator. A three-step protein extraction procedure provided protein samples for the determination of the target size (TS) of the covalently labelled estrogen receptor (ER). From the TS it is shown that ER bound to an antiestrogen was, in whole cells, part of a 265 kDa polypeptide structure if measured in MCF-7 cells at subconfluency, or of a 360 kDa species in superconfluent cells.
Toulas
C
C
Départment d'endocrinologie expérimentale, C.H.U. Rangueil, Toulouse, France.
Beauregard
G
G
Delassus
F
F
Thauvette
L
L
Potier
M
M
Bayard
F
F
Faye
J C
JC
D001943:Breast Neoplasms / Q000378:metabolism*; D003037:Cobalt Radioisotopes; D004591:Electrophoresis, Polyacrylamide Gel; D006801:Humans; D008970:Molecular Weight; D011960:Receptors, Estrogen / Q000302:isolation & purification / Q000378:metabolism* / Q000528:radiation effects; D013629:Tamoxifen / Q000031:analogs & derivatives / Q000378:metabolism; D014316:Tritium; D014407:Tumor Cells, Cultured
D003037:Cobalt Radioisotopes; D011960:Receptors, Estrogen; D013629:Tamoxifen; D014316:Tritium; C031859:tamoxifen aziridine